A quantitative index measured on 99mTc GSA SPECT/CT 3D fused images to evaluate severe fibrosis in patients with chronic liver disease

We compared quantitative indices estimated by use of technetium-99m galactosyl human serum albumin (99mTc-GSA) single-photon emission computed tomography (SPECT)/computed tomography (CT) fused imaging and hepatic fibrosis in patients with chronic liver disease. On the basis of pathological findings we divided 161 patients into non-severe and severe fibrosis groups (n=81 and n=80, respectively). We measured 2 indices by 99mTc-GSA SPECT/CT fused imaging: liver uptake value (LUV) = [radioactivity (whole liver)/radioactivity (injected)] x 100/body surface area, and functional liver index (FLI)=[radioactivity (hepatocytes)/radioactivity (injected)] x 100/liver volume. We compared these indices with biochemical and histopathological results. Univariate and multivariate analyses showed that FLI, LUV, liver and heart ROIs at 15 min post-injection (LHL15), and prothrombin time were significant independent predictors of severe fibrosis. On the basis of receiver operating characteristics analysis, the areas under curve values of FLI, LUV, LHL15, and prothrombin time for predicting severe fibrosis were 0.83, 0.73, 0.69, and 0.68, respectively. Using an FLI value of 0.053, it was possible to predict severe fibrosis with 65% sensitivity, 88% specificity, and 76% accuracy. Assessment of functional hepatocytes by use of 99mTc-GSA SPECT/CT fused images is useful for identifying pathological liver fibrosis. (author)